As the flu-vaccine shortage began, Canada quickly emerged as a potential life buoy. Ujjal Dosanjh, Canada's Health Minister, personally phoned Tommy Thompson, the U.S. Secretary of Health and Human Services, and offered to share whatever surplus Canada had to help meet the 48-million-dose shortfall. "I assured him that if there was anything we could do to assist our American friends, we would be happy to do that," Dosanjh told TIME. But it wasn't long before Dosanjh was spelling out the limits of what his country could do. "Canada cannot be the drugstore of the United States," he said last week in a speech at Harvard....